MEDICAL 


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St.   Louis  University 
School   of  Medicine . 


Original  Contributions  Concerning 

the  Glandular  Structures  Appertaining 
to  the  Human  Eye  and  its  Appendages. 


WITH  71  ORIGINAL  ILLUSTRATIONS. 


BY   ADOLF   ALT,  M.  D., 

PROFESSOR  OF  OPHTHALMOLOGY  IN  BEAUMONT 

HOSPITAL  MEDICAL    COLLEGE, 

ST.   LOUIS. 


ST.  LOUIS,  MO. 
1900. 


A  4  (a 


ORIGINAL  CONTRIBUTIONS  CONCERNING  THE 
GLANDULAR  STRUCTURES  APPERTAINING  TO 
THE  HUMAN  EYE  AND  ITS  APPENDAGES.* 

ADOLF  ALT,  M.  D. 

PREFACE. 

The  studies  and  investigations  which  are  the  subject  of  this 
paper  are  the  outcome  of  a  desire  to  have  as  clear  as  possible 
an  understanding  of  the  glandular  structures  appertaining  to 
the  human  eye  and  its  appendages  from  personal  knowledge. 

It  took  a  number  of  years  to  accumulate  the  very 
numerous  specimens,  the  careful  study  of  which  furnished 
the  basis  for  the  descriptions  here  given.  While  part  of  the 
many  eyelids  which  I  have  examined  were  obtained  from  suit- 
able cases  in  my  own  practice,  a  large  number  came  from  the 
dissecting  rooms  of  the  Beaumont  Hospital  Medical  College 
of  this  city  through  the  kindness  of  Dr.  R.  W.  Baker,  the 
demonstrator  of  anatomy  in  this  institution.  Of  necessity  a 
great  part  of  this  anatomical  material  was  of  a  pathological 
character,  and  it  has,  therefore,  served  for  other  studies  as 
well. 

As  it  seemed  to  me  that  the  text-books  which  I  know  of, 
with  but  few  exceptions,  deal  in  a  very  insufficient  manner 
with  this  interesting  subject,  I  have  thought  it  might  be  of 
some  interest  to  place  the  results  of  my  own  investigations 
in  this  direction  before  the  ophthalmic  public.  This  may, 
perhaps,  prove  the  more  interesting,  since  by  the  efforts  of 
numerous  foreign  ophthalmic  surgeons,  and  in  this  country 
notably  of  Dr.  C.  R.  Holmes  of  Cincinnati  t  the  old  operation 
of  the  removal  of  the  lacrymal  glands  for  incurable  lacryma- 


*  Presented  by  title  to  The  Academy  of  Science  of  St.  Louis,  May  21, 
1900. 

t  Archives  of  Ophthalmology.  28:1. 

1 


tion  has  of  late  been  reintroduced  and  has  become  a  legiti- 
mate surgical  procedure. 

The  investigations  herein  recorded  may  claim  to  be  original 
in  so  far  as  they  were  made,  in  a  sense,  as  if  I  had  known 
nothing  of  the  literature  on  the  subject.  This  was  in  reality 
the  case  with  some  of  the  more  recent  monographs  which  I 
did  not  and  had  no  chance  to  consult  until  my  researches, 
at  least  as  far  as  my  material  would  allow  me,  were  finished. 

The  illustrations,  except  the  three  last  ones,  which  are  more 
or  less  schematic  drawings,  are  made  from  photographs  1 
took  of  my  own  specimens. 

THE  ORBITAL,  PALPEBRAL  AND  CONJUNCTIVAL  LACRYMAL 

GLANDS. 

The  lacrymal  gland  is  usually  spoken  of  as  consisting  of 
two  separate  parts,  one  the  so-called  orbital  lacrymal  gland 
and  the  other  termed  the  inferior,  palpebral,  conjunctival  or 
accessory  lacrymal  gland. 

The  orbital  lacrymal  gland,  as  its  name  denotes,  is  situated, 
at  least  to  its  greatest  extent,  within  the  orbital  cavity.  There 
it  is  located  in  the  f  ovea  lacrymalis  which  lies  right  behind  the 
outer  upper  bony  orbital  margin  in  the  processus  zygomaticus  of 
the  frontal  bone.  Its  anterior  end  usually  slightly  protrudes 
beyond  the  bony  margin.  The  gland  is  held  in  this  position 
by  a  connective  tissue  capsule  which  is  united  with  the  orbital 
periosteum  by  means  of  loosely  interwoven  trabeculae.  This 
capsule  is  generally  somewhat  firmer  on  the  nasal  side  of  the 
gland. 

When  this  gland  is  in  toto  removed  from  the  fovea  lacry- 
malis, its  shape  is  seen  to  resemble  to  some  extent  that  of  an 
almond  (Fig.  1).  It  is  convex  at  the  orbital  surface,  and 
more  or  less  concave  at  its  ocular  (lower)  side.  Its  posterior 
portion  is  usually  thick  and  rounded,  its  anterior  one  thinner 
and  sharper.  The  posterior  part  of  the  gland  may,  when  it  is 
well  developed,  reach  back  into  the  orbit  about  as  far  as  the 
anterior  third  of  its  depth.  The  nasal  edge  usually  reaches 
to  the  temporal  margin  of  the  superior  rectus  muscle. 

However,  the  actual  measurements  of  this  gland,  like  those 
of  other  glands,  are  subject  to  great  variations.  As  an  inter- 


esting  fact,  I  may  say,  that  in  the  Negro  I  have  found  this 
gland  to  be  as  a  rule  larger  than  in  the  Caucasian.  I  have 
seen  it  often  to  be  twice  as  large  or  even  more  (Figs.  2,  3). 
The  orbital  lacrymal  gland  forms  a  more  or  less  compact 
glandular  body.  It  consists  of  a  large  number  of  lobules 
united  closely  with  each  other  by  loose  connective  tissue  in 
which  its  ducts  and  numerous  blood  vessels  lie.  These  con- 
nective tissue  trabeculae  are  united  to  its  capsule. 

The  gland  is  of  the  acinous  type  and  its  structure  has  been 
correctly  likened  to  that  of  the  serous  or  salivary  glands. 
The  round  or  oval  final  acini  are  situated  around  and 
connected  with  small  efferent  ducts  which,  by  their  union  in 
the  direction  towards  the  conjunctiva,  form  larger  and  larger 
excretory  ducts.  These  acini  consist  of  a  membrana  propria 
and  a  lining  of  cylindrical,  or  rather,  conical  secretory  epithe- 
lial cells,  with  a  large  round  or  oval  nucleus  near  their  broader 
base  which  are  arranged  in  a  circle  around  a  central  lumen. 

The  secretion  of  this  gland  is  carried  to  the  conjunctival 
sac  by  means  of  a  varying  number  of  these  excretory  ducts 
which  are  lined  with  a  cylindrical  epithelium.  The  statement 
is  made  by  numerous  authors,  that  there  are  from  6  to  12 
such  excretory  ducts.  It  does  not  seem  to  me  that  there  are 
so  many.  I  often  found  one  of  them,  which  also  seemed  to 
be  the  longest,  to  be  considerably  wider  than  the  others. 

These  excretory  ducts  reach  the  conjunctiva  of  the  fornix 
by  a  somewhat  bent  and  wavy  course ;  their  external  orifices 
lie  in  the  temporal  part  of  the  conjunctival  sac  near  the  edge 
of  the  tarsal  tissue. 

Below  the  orbital  lacrymal  gland  and  separated  from  it  by 
its  capsule,  the  levator  palpebrae  superioris  muscle  and 
Mueller's  non-striated  muscle,  and  embedded  in  the  loose 
connective  tissue  of  the  eyelid  on  the  temporal  side  of  the 
tarsus,  lies  the  inferior  or  palpebral  lacrymal  gland  (Figs. 
1  to  5 ) . 

This  gland  consists  of  a  varying  number  of  smaller  and 
larger  lobules  which  are  very  much  more  loosely  held  together 
by  the  intervening  connective  tissue  than  those  of  the  orbital 
gland,  and  therefore  do  not  form  as  compact  a  body. 

While  this  gland  is  usually  thought  to  lie  in  the  upper  eye- 


lid  alone,  I  have  in  normal  lids  almost  invariably  found  its 
lobules  to  reach  downwards  through  and  beyond  the  outer 
canthus  into  the  lower  eyelid  (Figs.  6,  7).  The  gland- 
ular lobules  here  lie  grouped  around  the  temporal  and  some- 
times even  the  lower  edge  of  the  tarsus.  Similar  lobules  of 
glandular  tissue,  only  still  more  loosely  connected  with  and 
further  apart  from  each  other,  are  found  in  most  eyelids  to 
extend  from  the  more  compact  temporal  body  of  this  palpebral 
glandular  system  towards  the  nasal  side  of  the  upper  eyelid. 
These  more  isolated  lobules  may  reach  to  the  middle  line 
of  the  eyelid  and  even  somewhat  beyond  it  (Figs.  8,  9). 
They  lie  in  the  loose  tissue  of  the  fornix  of  the  conjunctiva 
or  a  little  below  it  on  the  palpebral  side.  The  farther  away 
from  the  outer  canthus,  the  smaller  these  glandular  lobules 
usually  are.  Those  found  in  the  temporal  side  of  the  lower 
eyelid  seem  to  be  of  a  more  uniform  size.  Yet,  there  is  no 
absolute  rule  about  this. 

It  seems  that  when  speaking  of  the  palpebral  or  inferior 
lacrymal  gland,  we  have  to  include  all  of  these  separate  and 
so  widely  dispersed  glandular  lobules.  Their  number  in  the 
aggregate  may  well  reach  up  to  40  or  more. 

The  structure  of  the  glandular  lobules  is  exactly  the  same 
as  that  of  the  orbital  lacrymal  gland.  They  differ  in  no 
particular.  Their  numerous  efferent  ducts,  lined  with  cylin- 
drical epithelium,  lead  their  secretion  to  the  conjunctival  sac 
(Fig.  10).  The  statement  has  often  been  made  and 
repeated,  that  the  ducts  of  these  glands  are  taken  up  by 
those  of  the  orbital  lacrymal  gland  around  which,  in  part, 
they  are  grouped,  before  reaching  the  conjunctival  surface. 
Whether  this  happens  often,  I  cannot  tell  definitely  in  spite 
of  my  numerous  specimens ;  but  it  may  occasionally  be  the 
case.  I  find,  that  most  frequently  several  of  these  lobules 
have  an  excretory  duct  in  common,  which  runs  separately  from 
the  excretory  ducts  of  the  orbital  lacrymal  gland  to  the  con- 
junctiva. Such  a  duct  has  generally  a  wavy  course  and  does 
not  reach  the  conjunctiva  by  the  shortest  route  ( Figs.  10  to  16 ). 
The  more  widely  separated  and  the  totally  isolated  glandular 
lobules  in  the  lower  eyelid  and  those  glands  which  extend  in 
the  upper  eyelid  towards  its  middle  line,  must  of  necessity 


have  their  ducts  apart  from  those  of  the  orbital  lacrymal 
gland,  as  they  lie  so  far  removed  from  them.  The  external 
orifices  of  these  ducts  lie  in  the  upper  conjunctival  fornix  and 
usually  form  a  row,  being  arranged  side  by  side.  I  may  state 
here,  that  these  excretory  ducts  pierce  the  conjunctival  sur- 
face generally  at  a  more  or  less  acute  angle  in  a  downward 
direction,  so  that  the  upper  lip  overhangs  the  orifice  (Figs. 
11,  14). 

Even  in  what  appear  to  be  perfectly  normal  conjunctivae, 
the  orfiices  of  the  ducts  are  frequently  surrounded  by  a  dense 
lymphoid  infiltration  in  the  adjoining  tissue.  This  infiltration 
is  frequently  so  dense  that  on  surface  specimens  it  may  hide 
the  openings.  This  condition  may,  perhaps,  be  the  explana- 
tion for  the  repeated  statements  that  in  the  normal  conjunc- 
tiva of  man  lymph-follicles  could  be  found.  I  here  repeat 
the  statement  which  I  have  made  on  other  occasions,  that,  like 
Waldeyer,  I  have  never  found  a  true  lymph-follicle  in  the 
human  conjunctiva. 

From  the  foregoing  description  it  is  apparent  that  a  very 
large,  though  varying,  amount  of  glandular  tissue,  of  identi- 
cally the  same  structure  and  most  probably  the  same  function 
as  the  orbital  lacrymal  gland,  is  situated  in  the  temporal  half 
of  the  eyelids  above,  respectively  below,  the  fornix  conjunc- 
tivae. The  secretion  of  all  of  these  glands,  combined  with 
that  of  the  orbital  lacrymal  gland,  is  discharged  into  the  con- 
junctival sac  and,  flowing  over  the  surface  of  the  eyeball, 
keeps  it  and  the  inner  surfaces  of  the  eyelids  moist. 

Yet,  even  a  careful  removal  of  all  of  this  glandular  tissue 
does  not  render  the  surface  of  the  eyeball  dry.  There  must, 
therefore,  be  still  other  glandular  structures,  which  supply 
such  a  moistening  liquid,  and,  in  reality,  a  number  of  such 
glands  do  exist. 

Almost  without  exception  1  find  one  such  gland,  consisting 
of  2  or  3,  seldom  4  lobules,  near  the  inner  canthus  in  the 
nasal  part  of  the  upper  eyelid,  or  a  little  higher  up  in  the  con- 
junctiva near  the  fornix  (Figs.  17  to  20);  another  one,  con- 
sisting usually  of  2  lobules,  I  find  in  the  nasal  conjunctiva  of 
the  lower  eyelid,  below  the  lacrymal  caruncle  (Figs.  21,  22), 
and  frequently  one  in  the  temporal  side  of  the  lower  eyelid 


somewhat  nasally  removed  from  the  palpebral  lacrymal 
gland. 

When  studying  horizontal  sections  through  the  eyelids  such 
little  glands  are  sometimes  found,  also,  to  lie  close  to  the 
temporal  and  nasal  edges  of  the  tarsus  of  the  upper  as  well 
as  the  lower  lid,  and  partly  in  the  ocular  conjunctiva.  They 
are  formed  of  one  or  two  minute  glandular  lobules.  All  of 
these  glands  are  of  exactly  the  same  histological  structure  as 
those  generally  recognized  as  lacrymal  glands.  Their  ex- 
cretory ducts,  from  their  situation,  are  rather  short.  They, 
also,  are  lined  with  cylindrical  epithelium.  Their  external 
orifice  lies  usually  in  the  palpebral,  sometimes  in  the  ocular 
conjunctiva  (Figs.  23  to  25). 

There  is  no  reason,  as  far  as  I  can  see,  why  these  small 
isolated  acinous  glands  should  not  also  be  looked  upon  as 
lacrymal  glands,  as  they  differ  in  no  way  histologically  from 
them.  The  difference  in  size  is  the  only  one  I  can  recognize. 

The  presence  of  these  glands  alone,  then,  could  explain 
why,  after  the  operative  removal  or  the  destruction  of  the 
orbital  and  the  larger  palpebral  lacrymal  glands  in  the  tem- 
poral half  of  the  eyelids,  the  surfaces  of  the  eyeball  and  eye- 
lids do  not  become  dry.  It  is,  furthermore,  clear  that  when 
a  chronic  inflammation,  involvingthe  whole  of  the  conjunctiva, 
gradually  leads  to  its  shrinkage  and  to  the  consequent  oblitera- 
tion of  the  excretory  ducts  and  secondarily  to  atrophy  of  all 
these  glands  (and  of  some  to  be  described  presently),  as  for 
instance  trachoma,  xerophthalmus  must  result. 

GLANDS     SITUATED    IN     THE    TARSAL     TISSUE     OF    THE    EYELIDS. 

The  tarsal  tissue  proper  of  the  eyelids  contains  two  forms 
of  glands,  namely,  the  so-called  Meibomian  glands  and  the 
acino-tubular  (Waldeyer)  glands. 

The  Meibomian  glands  are  found  in  the  upper  lid  to  be 
about  30  in  number,  while  in  the  lower  lid  they  are  only 
about  20.  There  are,  however,  individual  variations  as 
to  these  numbers.  They  are  long,  slender  glandular  struc- 
tures, somewhat  resembling  the  pancreatic  glands,  consisting 
each  one  of  a  central  duct  to  which  are  attached  numerous 
round,  vesicle-like  acini  (Fig.  26).  These  central  ducts 


never  quite  reach  the  upper  (in  the  lower  eyelids  the  lower) 
edge  of  the  tarsus.  The  acini  begin  somewhat  removed  from 
the  external  orifice  of  this  central  duct  and  sit  upon  it  very 
much  like  grapes  on  the  central  stem.  They  form  usually 
four  rows  around  it,  one  on  the  posterior  and  one  on  its 
anterior  surface,  one  on  its  nasal  and  one  on  its  temporal  side 
(Figs.  27,  28).  The  external  orifices  of  the  excretory  ducts 
lie  side  by  side  at  the  free  edge  of  the  lid  behind  the  lashes. 
The  dermal  epithelium  reaches  inwards  into  these  ducts  for 
some  distance,  as  is  particularly  well  shown  in  the  eyelids  of 
the  Negro  (Fig.  26). 

The  acini  of  these  glands  as  well  as  their  ducts  are  lined 
with  several  layers  of  flat  polygonal  epithelial  cells.  These 
continually  undergo  a  fatty  degeneration  and  thus  form  a 
sebaceous  secretion  which  renders  the  lidmargins  fatty  and 
thus  helps  to  retain  the  tear-fluid  within  the  conjunctival 
sac.  In  their  structure  these  glands  differ  in  no  way 
from  the  sebaceous  glands  of  the  skin ;  they  differ  only  in 
size. 

The  length  of  the  individual  Meibomian  glands  varies  ac- 
cording to  the  height  of  the  tarsal  tissue.  Thus,  the  longest 
ones  lie  in  the  middle  line  of  the  eyelid,  and  from  there  they 
grow  gradually  shorter  towards  both  canthi.  The  most 
nasally  or  temporally  situated  ones  often  consist  only  of  the 
central  duct  and  two  or  three  acini. 

I  can  find  only  one  layer  of  Meibomian  glands,  and  all 
statements,  referring  to  two  or  even  more  layers,  are  un- 
doubtedly due  to  oblique  sections.  In  a  general  way  these 
glands  run  parallel  to  each  other  and  at  right  angles  to  the 
lidmargin.  Yet,  deviations  from  this  rule  are  not  uncommon 
(Fig.  28). 

The  second  kind  of  glands,  the  acino-tubular  ones  (Wald- 
eyer),  are  usually  drawn  and  described  as  lying  solely  in  the 
temporal  part  of  the  tarsus  above  (in  the  lower  lid  below)  the 
Meibomian  glands  (Fig.  29  to  31).  This  seems  to  be  their 
most  frequent  location,  or  at  least,  they  seem  to  be  generally 
best  developed  in  this  portion  of  the  tarsus.  They  are  how- 
ever, at  least  in  the  upper  eyelid,  quite  frequently  found  to 
be  located,  also,  near  and  in  the  middle  line  (Figs.  23  to  25), 


and  sometimes,  but  rarely  so,  near  the  nasal  edge  of  the  tarsus 
(Fig.  32).  While,  as  a  rule,  they  are  situated  between  the 
apex  of  the  Meibornian  glands  and  the  upper  (in  the  lower 
eyelid  the  lower)  edge  of  the  tarsus,  they  are  not  at  all  in- 
frequently found  to  reach  in  between  the  Meibomian  glands 
and  as  far  down  (or  up)  almost  as  the  orifices  of  &these 
glands  at  the  lidmargin  (Figs.  32  to  35). 

The  histological  structure  of  these  glands  is  also  of  the 
acinous  type,  and  they  do  not  essentially  differ  from  the 
lacrymal  glands,  although  their  appearance  and  general  ar- 
rangement are  slightly  modified  by  the  dense  tissue  in  which 
they  lie  embedded  (Figs.  36,  37).  Their  lobules  are 
formed  of  numerous  round  and  oval  acini  which  consist  of  a 
basal  membrane  lined  with  cylindrical  (conical)  cells  arranged 
around  a  central  lumen,  with  a  round  or  oval  nucleus  near 
their  base.  The  small  excretory  ducts  coming  from  the  acini 
unite  into  a  larger  one  which  is  sometimes  quite  long  and  to 
which  smaller  acini  are  attached  throughout  its  length,  the 
small  ducts  of  which  empty  directly  into  this  large  duct 
formed  by  the  union  of  the  ducts  coming  from  the  most  dis- 
tant acini.  It  is  probably  this  arrangement  which  has  led  to 
their  being  named  "  acino-tubular "  glands.  Sometimes, 
however,  and  especially  when  these  glands  are  situated  be- 
tween the  Meibomian  glands,  this  excretory  duct  is  but  very 
short.  The  excretory  ducts  of  the  acino-tubular  glands  are, 
also,  lined  with  cylindrical  epithelium,  like  those  of  the 
lacrymal  glands.  Their  external  orifice  lies  in  the  palpebral 
conjunctiva  (Figs.  35,  38). 

These  acino-tubular  glands  are  generally  spoken  of  as  muci- 
parous  glands.  For  what  reason,  I  have  been  unable  to  deter- 
mine, and  it  is  not  possible  to  examine  their  secretion  chemi- 
cally. Their  structure  as  stated,  with  the  slight  modification  due 
to  density  of  the  tissue  in  which  they  lie  embedded,  corresponds 
in  every  respect  with  the  lacrymal  glands.  The  microscopi- 
cal staining  reagents  which  seem  to  have  a  special  affinity  to 
mucous  substances,  as  haematoxylin,  Bismark-brown,  and 
others,  do  not  stain  any  part  of  these  glands  in  particular. 
Now  and  then  I  have  found  a  concretion  in  the  excretory  duct 
of  such  a  gland,  but  this  cannot  be  taken  as  proof  of  their 


muciparous  character,  as  just  such  concretions  are  also  found 
in  the  ducts  of  the  lacrymal  glands  (Fig.  39). 

GLANDS  SITUATED  IN    THE  TISSUE    OF  THE  LIDMARGIN. 

In  the  dense  tissue  of  the  lidmargin,  in  front  of  the  excre- 
tory ducts  of  the  Meibomian  glands,  the  cilia  or  eyelashes  are 
implanted.  These  short  curved  hairs  form  three  or  four  rather 
irregular  rows  and  emerge  from  the  skin  of  the  anterior  part 
of  the  lidmargin  (Fig.  40).  They  are  more  numerous  in 
the  upper  eyelid  than  in  the  lower  one,  numbering  in  the 
former  from  100  to  150,  in  the  latter  from  50  to  70. 
These  numbers  are,  of  course,  only  approximately  correct. 
The  longest  eyelashes  lie  in  the  middle  line  of  the  lids  and 
from  here  they  grow  smaller  and  smaller  in  the  direction 
towards  the  canthi.  They  are  shortlived  and  drop  out  when 
about  from  50  to  100  days  old.  The  curvature  of  the 
eyelashes  of  the  upper  lid  is  concave  upwards  and  convex 
downwards,  while  that  of  the  eyelashes  of  the  lower  lid  is 
just  the  reverse. 

Each  eyelash  is  accompanied  by  sebaceous  glands,  usually 
two,  not  infrequently  three  and  four  to  one  hair.  These 
glands  do  not  differ  in  any  particular  from  other  sebaceous 
glands  of  the  hair  of  the  skin  and,  therefore,  it  is  not  neces- 
sary to  give  here  a  special  description . 

There  is,  however,  another  kind  of  glands  situated  in  the 
interinarginal  tissue  of  the  eyelids,  more  especially,  between 
the  roots  of  the  eyelashes,  which  is  of  a  somewhat  peculiar 
structure.  These  glands  have  been  called  modified  sweat- 
glands,  although,  as  far  as  I  can  find,  nothing  is  known  con- 
cerning the  character  of  their  secretion  (Figs.  41,  42). 

In  vertical  (sagittal)  sections  through  the  whole  thickness 
of  the  eyelids  one  or  two  such  glands  are  usually  seen  to  lie 
between  the  roots  of  two   neighboring  eyelashes  or  a  little 
nearer  to  the  lidmargin,  sometimes  farther  inwards  between 
the  eyelashes  and  the  tarsal  tissue.     In  horizontal  sections 
(Fig.  43)  and  sections  which  are  made  parallel  to  the  surface 
of  the  eyelid,  these  glands  are  often  found  to  be  very  numer- 
ous.    (I  have  never  succeeded  in  getting  such  sections  par- 
allel to  the  surface  which  would  go  through  the  whole  width 


10 

of  the  eyelid  on  account  of  its  curvature,  but  they  often  com- 
prise about  half  or  a  little  more  of  an  eyelid.  For  the  same 
reason,  that  is,  the  curvature  of  the  eyelid,  these  sections  can 
only  in  an  approximate  way  be  said  to  run  parallel  to  the 
surface  of  the  eyelid.) 

Near  the  canthi  where  the  eyelashes  cease,  I  find,  as  a  rule, 
a  larger  body  of  these  glandular  structures  lying  outside  of 
the  last  eyelash,  temporally  as  well  as  nasally. 

These  peculiar  glands  usually  appear  to  consist  of  one  or 
two  rows  of  round  or  oval  vesicle-like  acini,  which  are  some- 
times quite  large,  and  which  probably  communicate  with  each 
other  (Figs.  44,  45).  Half  a  dozen  or  so  of  such  acini 
seem  to  constitute  the  gland.  These  usually  terminate  in  one 
larger,  more  conically  shaped  acinus,  a  collecting  chamber, 
from  which  the  efferent  duct  of  the  gland  takes  its  origin. 
While  this  arrangement  is  the  one  I  have  almost  always  found, 
I  have  now  and  then  seen  a  gland  which  appeared  to  be  alto- 
gether tubular,  the  tube  being  wound  upon  itself  exactly  as  is 
the  case  with  the  sweat-glands  of  the  skin  (Figs.  42,  46). 
As  this  usually  occurred  in  thicker  sections  it  may,  perhaps, 
be  that  the  appearance  I  have  above  described,  is  due  to  the 
manner  in  which  the  section  has  cut  through  the  windings 
of  the  tube,  and  that  in  reality  we  have  to  deal  altogether 
with  tubular  glands.  I  have  been  unable  to  come  to  a  definite 
conclusion  as  regards  this  point. 

The  efferent  duct  of  these  glands  usually  has  a  slightly 
arched  course  on  its  way  to  the  lidmargin  (Figs.  41,  42). 
There  its  orifice  lies  frequently  within  the  duct  of  one  of  the 
sebaceous  glands  belonging  to  an  eyelash.  There  are,  how- 
ever, many  exceptions  to  this  general  rule,  and  I  have  found 
in  almost  every  eyelid  a  number  of  external  orifices  of  effer- 
ent ducts  of  modified  sweat-glands  which  lie  separately  in 
the  skin  of  the  lidmargin. 

The  acini  of  these  peculiar  glands  are  lined  with  a  short, 
almost  cuboid  cylindrical  epithelium  ;  the  epithelial  cells  lining 
the  efferent  ducts  appear  more  flattened. 

I  have  frequently  seen  a  fatty,  grumous  substance  contained 
in  the  lumen  of  the  acini  of  these  glands  which  appeared 
exactly  like  the  contents  found  in  the  acini  of  the  Meibomian 


11 

glands.  Like  these  it  did  Dot  take  up  any  stain  and  it  was 
dissolved  and  totally  disappeared,  as  soon  as  the  specimen 
was  cleared  in  oil  of  cloves.  Of  course,  it  is  not  permissible 
to  conclude  from  this  fact  alone  that  these  glands  must  be 
looked  upon  rather  as  modified  sebaceous  than  as  modified 
sudoriferous  glands.  Still,  I  think  this  point  is  worth  men- 
tioning. Neither  does  it  seem  very  apparent,  what  role  a 
watery  secretion  should  play,  when  mixed  with  the  fatty  secre- 
tion of  the  sebaceous  glands  of  the  eyelashes.  Furthermore, 
a  watery  secretion  in  this  region  would  very  likely  lead  to 
the  overflow  of  the  tears  at  the  lidmargin,  which  is  evidently 
not  the  case. 

THE     CARUNCULA    LACRYMALIS    AND    THE    GLANDS    SITUATED    IN 

ITS    TISSUE. 

The  little  rounded  body  of  tissue  lying  at  the  nasal  can- 
thus  between  and  slightly  backwards  from  the  folds  coming 
from  the  upper  and  lower  eyelids,  which  is  called  the  lacry- 
mal  caruncle,  consists  to  a  large  extent  of  glandular  tissue  and 
bears  some  small  hairs  on  its  surface. 

In  vertical,  as  well  as  in  horizontal  sections  through  this 
body,  I  find  usually  three  larger  sebaceous  glands  which, 
except  in  their  smallness,  differ  in  no  particular  from  the 
Meibomian  glands  of  the  eyelids.  They  have  the  same  cen- 
tral duct  and  the  same  acini,  only  in  a  more  compact  arrange- 
ment (Fig.  47). 

Now  and  then  one  or  two  of  the  so-called  modified  sweat- 
glands  are  found  between  them,  lying  usually  in  the  center 
of  the  body  of  the  caruncle.  They  differ  from  those  found 
in  the  tissue  of  the  lidmargin  only  by  being  smaller  and 
shorter. 

With  much  more  regularity,  indeed,  almost  as  a  rule,  I  find 
one,  and  quite  often  two,  small  glandular  bodies  of  theacinous 
type  situated  in  the  lacrymal  caruncle  (Figs.  47  to  50). 
One  of  these  usually  lies  near  the  upper  and  the  other  nearer 
the  lower  edge  of  the  caruncle.  They  differ  in  their  struc- 
ture in  no  way  from  the  acinous  glands  found  in  the  con- 
junctiva and  eyelids,  and  are,  therefore,  probably  little  lacry- 
mal glands  like  these.  At  least  they  do  not  react  differently 


12 

against  staining  reagents  and  more  especially  they  do  not  show 
any  staining  affinity  which  would  prove  that  they  are  of  a 
muciparous  character. 

Their  short  excretory  ducts  are  lined  with  cylindrical  epi- 
thelium, and  their  external  orifice  lies  either  on  the  surface 
of  the  lacrymal  caruncle  or  in  the  plica  semilunaris. 

Aside  from  these  glandular  structures,  usually  some  fat- 
tissue  is  inclosed  in  the  connective  tissue  which  forms  the 
body  of  the  caruncle.  In  one  case,  and  in  one  only,  I 
found  a  small  amount  of  hyaline  cartilage  tissue  embedded  in 
the  loose  connective  tissue  near  the  lower  margin  of  the 
lacrymal  caruncle  and  between  it  and  the  plica  semilunaris 
(Figs.  51,  52). 

THE    LACRYMAL   DRAINAGE    APPARATUS. 

The  tear  fluid  which  has  neither  been  evaporated  nor  used 
up  in  moistening  the  surfaces  of  the  eyeball  and  the  eyelids, 
is  drained  off  into  the  nose  at  the  nasal  angle  of  the  palpebral 
fissure  by  means  of  a  special  system  of  draining  tubes. 

This  draining  apparatus  begins  with  the  lacrymal  puncta, 
two  small  oval  openings  which  are  situated  at  the  apex  of  the 
lacrymal  papillae.  These  papillae  are  little  cone-shaped  ele- 
vations which  lie  in  the  lidmargins  in  line  with,  and  to  the 
nasal  side  of,  the  orifices  of  the  Meibomian  glands  in  the 
tarsal  part  of  the  eye-lids.  The  lower  papilla  lies,  as  a  rule, 
a  little  farther  removed  temporally  from  the  inner  canthus, 
than  the  upper  one. 

From  the  puncta  the  lacrymal  canaliculi  start  by  which  the 
tear-fluid  is  carried  to  the  lacrymal  sac.  Each  canaliculus 
may  be  divided  into  two  parts,  namely,  a  more  or  less  vertical 
(Fig.  53)  and  a  more  or  less  horizontal  one  (Fig.  54).  The 
first  part,  which  is  by  far  the  shorter,  runs  from  the  lacrymal 
punctum  upwards  (in  the  lower  eyelids  downwards),  and  in- 
wards, nearly  at  a  right  angle  to  the  lidmargin.  It  is  from 
1.5  to  2  mm.  long.  The  second,  the  so-called  horizontal, 
part,  runs  in  the  direction  towards  the  nose  until  it  reaches 
the  lacrymal  sac. 

Just  inwards  from  its  orifice  at  the  lacrymal  punctum  the 
vertical  part  is  generally  very  narrow  (Fig.  55),  and  then 


13 

widens  out  more  gradually.  Where  it  makes  the  sudden 
bend  to  form  the  horizontal  part,  it  usually  has  a  diverticle 
(Fig.  56),  which  bulges  out  from  its  temporal  side  into  the 
tissue  of  the  eyelid.  This  diverticle  is  formed  just  at  the 
end  of  the  vertical  part,  and  runs  in  a  horizontal  direction  and 
is  sometimes  comparatively  large.  Quite  frequently  there  is 
another  diverticle  in  the  horizontal  part  just  at  its  beginning 
which  runs  in  a  more  vertical  direction. 

The  horizontal  part  of  the  upper  canaliculus  is  about  7 
mm.  long  and  that  of  the  lower  canaliculus  is  a  little  longer. 
As  stated  above,  the  course  of  this  portion  of  the  canaliculi 
is  not  in  reality  horizontal,  as  the  two  gradually  bend  toward 
each  other.  Moreover  this  part  of  the  canaliculi  does  not  run 
in  a  straight  line,  so  to  speak,  but  is  quite  wavy,  sometimes 
even  tortuous  (Fig.  57). 

Just  before  reaching  the  temporal  wall  of  the  lacrymal  sac 
the  two  canaliculi  may,  and  as  a  rule  do,  join  together  and 
form  one  larger  collective  tube  (Fig.  58).  The  length  of  this 
tube  varies  materially  in  different  individuals,  and  it  may  be 
so  short  that  it  can  hardly  be  recognized  as  a  separate  part. 
In  other  cases  the  two  canaliculi  reach  and  enter  the  lacrymal 
sac  separately  and  ununited. 

From  their  beginning  at  the  lacrymal  puncta  to  their  en- 
trance into  the  lacrymal  sac  the  canaliculi  are  formed  by 
a  membrana  propria,  the  connective  tissue  of  which  is  largely 
intermingled  with  elastic  elements.  This  membrana  propria 
is  lined  with  laniellated  polygonal  pavement  epithelium 
(Fig.  59)  which  often  forms  a  dozen  or  even  more  layers, 
seldom  fewer  than  ten. 

By  means  of  these  canaliculi,  as  stated,  the  tear-fluid  is 
drained  from  the  conjunctival  sac  into  the  larger  receptacle, 
the  lacrymal  sac,  and  again  from  this  into  the  nose  by  means 
of  the  nasal  lacrymal  duct. 

The  lacrymal  sac  (Fig.  60),  lies  in  the  fossa  lacrymalis 
formed  by  the  lacrymal  bone  and  the  frontal  process  of  the 
supramaxillary  bone,  and  between  the  branches  of  the  internal 
palpebral  ligament.  It  forms  a  comparatively  narrow,  almost 
slit-like,  cavity,  which  has  a  great  many  diverticles  and  folds. 
Its  epithelium  consists  of  a  basal  layer  of  more  cuboid  cells 


14 

and  of  an  inner  layer  of  cylindrical  cells.     I  have  never  seen 
ciliated  cells  (Figs.  59,  61). 

The  material  of  lacrymal  sacs  which  I  have  been  able  to 
obtain  for  microscopical  study  has  been  rather  limited  and  I 
have  seldom  had  an  entire  lacrymal  sac  for  examination. 
Usually  it  was  only  the  upper  and  temporal  part.  I  there- 
fore cannot  give  from  my  own  knowledge  a  more  detailed 
description  of  its  structure  and  will  refer  only  to  one  point  of 
interest,  which,  more  especially,  belongs  to  this  paper,  deal- 
ing, as  it  is,  with  the  glandular  organs  belonging  to  the  eye- 
ball and  its  appendages. 

It  has  been,  and  still  is,  a  moot  question,  whether  or  not 
true  glandular  tissue  is  found  in  the  walls  of  the  lacrymal 
sac.  From  my  specimens  I  cannot  see  how  the  existence  of 
such  glandular  tissue  can  be  doubted.  As  to  the  character  of 
the  glands  and  their  secretion  we  can  only  speculate  by  com- 
parison with  other  glands.  I  find  usually  two  forms  of  glands 
and  both  of  these  often  in  considerable  numbers,  especially  in 
the  wall  opposite  the  entrance  of  the  collecting  tube  of  the 
canaliculi. 

The  one  kind  is  of  the  acinous  type  and  corresponds  in  its 
structure  exactly  with  the  acinous  glands  found  in  the  eye- 
lids, conjunctiva  and  caruncle  (Figs.  62  to  66).  The  struc- 
ture of  the  other  kind  is  more  that  of  tubular  glands,  like  the 
sudoriferous  glands  (Figs.  67,  68.) 

I  have  never  had  an  occasion  to  examine  the  structure  of 
the  nasal  lacrymal  duct. 

REMARKS    ON    THE    LITERATURE   CONCERNING    THE    SUBJECTS    OF 

THIS    PAPER. 

In  how  far,  what  I  have  found  and  described  in  the  forego- 
ing pages  corresponds  with  or  disagrees  with  what  other 
investigators  on  this  subject  have  found  and  laid  down  in 
literature,  may  be  judged  from  the  following  brief  survey  of 
the  more  important  works  on  the  subject  from  the  literature 
at  my  disposal. 

I  started  out  more  particularly  on  this  investigation,  because 
I  could  get  no  satisfactory  explanation  as  to  what  glands 
were  referred  to  by  the  different  authors,  when  speaking  of 


15 

the  "  glands  of  Krause."  As  I  could  not  procure  Krause's 
own  original  description  *  I  had  to  rely  on  what  the  text-books 
could  give  me,  and  this  is  what  I  found. 

H.  Freyt  states  that  "  in  man  we  find  small  acinous 
glands,  so-called  mucous  glands  (according  to  Henle  '  acces- 
sory lacrymal  glands  ').  They  lie  in  the  fornix  of  the  con- 
junctiva between  the  tarsal  tissue  and  the  eyeball,  and 
there  are  in  the  upper  eyelid  as  many  as  42  of  them,  in  the 
lower  eyelid  from  2  to  6." 

What  Frey  here  refers  to,  are  probably  the  lacrymal  glands 
forming  the  palpebral  or  inferior  lacrymal  gland  and  the 
adjoining  separate  lobules  which  I  have  described,  and  which 
together  may  number  about  40.  Why,  however,  he  calls 
them  mucous  glands,  Frey  does  not  explain. 

W.  Waldeyer  J  says:  "  The  acino-tubular  glands  in  man 
lie  in  certain  distinct  localities,  at  the  edge  of  the  tarsus  near- 
est the  fornix,  and  with  preference  in  its  nasal  part.  There 
they  are  found,  partially  along  the  edge  of  the  tarsus,  and 
partially  within  the  tissue  of  the  tarsus  itself.  They  are 
more  numerous  in  the  upper  eyelid  than  in  the  lower  one ;  ac- 
cording to  Krause  and  his  pupil  Kleinschmidt  there  are  about 
42  of  them  in  the  upper  and  from  6  to  8  in  the  lower  eyelid. 
Their  excretory  ducts  open  into  the  conjunctiva  of  the  fornix. 
The  glandular  body  belonging  to  an  excretory  duct  is  rela- 
tively large  and  consists  of  short  tubular  glandular  chambers 
to  which  round  acini  are  attached  in  large  numbers."  Yet, 
in  the  text  to  his  beautiful  illustration,  he  calls  the  acinous 
glands  lying  buried  wholly  within  the  tarsal  tissue  itself,  the 
acino-tubular  glands. 

Surely  it  is  utterly  impossible  from  these  two  apparently 
authoritative  descriptions  to  arrive  at  a  clear  and  distinct  idea 
of  what  is  meant  by  the  term  "  Krause's  glands."  Frey  calls 
them  mucous  glands  or,  with  Henle,  accessory  lacrvmal 
glands,  and  Waldeyer  states  that  they  lie  with  preference  in 


*  Zeitschrift  fur  rationelle  Medicin.  4: :  337.  (1854). 

t  Handbuch  der  Histologie  and  Histochemie  des  Menschen.  673.  Leipzig. 
1874. 

J  Handbuch  der  gesammten  Augenheilkunde,  von  A.  Graefe  u.  Th. 
Saemisch.  I1: 238.  Leipzig.  1874. 


16 

the  nasal  side  of  the  eyelid  and  calls  them  acino-tubular 
glands.  Yet,  both  of  these  authors  agree  in  stating  that 
they  found  42  such  glands  in  the  upper  eyelid,  and  but 
slightly  differ  as  to  the  minimum  number  in  the  lower 
eyelid,  while  they  again  agree  as  regards  their  maximum 
number. 

In  my  description  I  have,  therefore,  refrained  from  using 
this  term  for  any  of  the  glands  which  I  have  found.  I  may, 
however,  state  that  the  idea  of  most  authors  seems  to  be  that 
the  glands  which  are  found  in  the  conjunctiva  of  the  nasal 
part  of  the  upper  eyelid  are  "  Krause's  glands."  That  the 
number  of  these  glands  is  very  small  and  never  comes  near 
being  42,  has  been  seen  from  my  description.  That  number 
can  only  refer  to  the  palpebral  lacrymal  glands. 

E.  Fuchs*  says:  "  Upon  the  fornix,  especially  in  its  nasal 
half,  lie  the  acinous  glands  of  Krause,  while  in  the  temporal 
half  of  the  tarsus  are  found  lobules  similar  in  character  but 
more  densely  packed,  representing  the  inferior  lacrymal 
gland  "  This  may,  perhaps,  sound  differently  in  the  origi- 
nal. Certain  it  is,  that  the  inferior  or  palpebral  lacrymal 
gland  does  not  lie  in  the  tarsus. 

On  page  560  of  the  same  text-book,  Fuchs  makes  the  state- 
ment (translation)  that  the  inferior  lacrymal  gland  consists 
of  only  one  or  two  lobules,  for  which  reason  it  is  also  known 
as  the  accessory  lacrymal  gland. 

It  does  not  seem  possible  that  by  these  two  statements  he 
refers  to  one  and  the  same  glandular  structure. 

A  good  description,  both  of  the  orbital  and  of  the  inferior 
lacrymal  gland,  is  given  by  E.  Bock  in  a  monograph  on  the 
lacrymal  gland  in  health  and  disease. f 

The  best,  most  extensive  and  most  careful  researches  and 
descriptions,  and  those  which  most  nearly  correspond  with 
what  I  have  found,  were  made  by  A.  Terson,  whose  excellent 
monograph  t  has  come  to  my  knowledge  and  into  my  posses- 


*  Text-book  of  Ophthalmology.  Translated  by  A.  Duane.  2d  American 
edition.  New  York.  1899.  In  the  text  beneath  Fig.  164  (p.  561). 

t  Zur  Kenntniss  der  gesunden  und  krankenThraenendruese.  Wien.  1896. 

t  Les  glandes  lacrymales  conjonctivales  et  orbito-palp<Sbrales.  L'ab- 
lation  des  glandes  lacrymales  palpSbrales.  Paris.  1892. 


17 

sion  only  when  my  investigations  on  this  subject  were,  so  to 
speak,  closed. 

For  macroscopic  inspection  Terson  clears  the  whole  eye- 
lids up,  by  means  of  tartaric  or  acetic  acid.  He  says:  "  In 
the  outer  third  of  the  specimen  the  palpebral  lacrymal  gland 
with  its  own  excretory  ducts  and  those  of  the  orbital  lacrymal 
gland  is  plainly  seen."  Further  on  :  "It  is  not  difficult  to  recog- 
nize a  long  line  of  very  much  smaller  glands,  forming,  as 
Mr.  Panashas  so  happily  expressed  it,  a  sort  of  '  milky  way  '  in 
the  upper  conjunctival  cul-de-sac.  Of  these  glands  there  is  a 
continuous  row,  and  they  grow  gradually  larger  towards  the 
inner  angle." 

Further  on,  he  says :  "  In  the  lower  cul-de-sac  I  find  a  few 
glands  very  similar  to  those  in  the  upper  one,  but  they  do  not 
reach  the  inner  angle  and  are  situated  in  that  half  of  the 
lower  eyelid  which  lies  close  to  the  palpebral  lacrymal 
gland." 

In  these  particulars  Terson 's  description  varies  but  little 
from  my  own. 

His  description  of  the  acino-tubular  glands  in  the  tarsal 
tissue,  also,  agrees  very  well  with  mine.  His  experience  has, 
also,  been  that  these  glands  are  found  most  frequently  in  the 
temporal  half  of  the  tarsal  tissue,  but  often,  too,  in  the  nasal 
or  other  parts.  Contrary  to  my  experience,  he  finds  their 
excretory  ducts  to  be  very  long  and  very  tortuous.  He  also 
has  found,  that  their  duct  may  pass  down,  in  between  the 
Meibomian  glands.  He  further  states  that  the  epithelium  of 
these  glands  as  well  as  that  of  their  excretory  ducts  ap- 
pears identical  with  that  of  the  acinous  glands  of  the  fornix, 
and  that  the  external  orifices  of  the  excretory  ducts  of  the 
acino-tubular  glands  lie  in  the  conjunctiva  of  the  upper  cul- 
de-sac  or  at  other  points  of  the  tarsus  and  often  even  very 
near  the  lidmargin. 

From  this  it  would  appear,  that  he  never  found  such  acino- 
tubular  glands  in  the  lowr  eyelid. 

With  regard  to  the  glands  found  in  the  walls  of  the  lacry- 
mal sac,  a  very  exhaustive  paper  by  K.  Joerss  has  appeared 
as  No.  35  of  Deutschmann's  Beitraege  zur  Augenheilkunde, 
Leipzig,  October  29th,  1898.  (Beitraege  zur  normalen  and 


18 

pathologischen  Histologie  des  Thraenenschlauches).  Joerss 
made  his  studies  on  excised  lacrymal  sacs,  and  one  of  his  ob- 
jects was  to  see,  whether  true  glands,  could  be  found  in  the 
lacrymal  sac,  or  not.  In  consequence,  he  devotes  consider- 
able space  to  this  question  and  his  conclusion  is  that,  contrary 
to  the  statements  of  other  investigators,  true  glands  are  really 
sometimes  found  lying  in  the  normal  mucous  membrane  of 
the  lacrymal  sac;  but,  according  to  his  investigation,  they  are 
serous  glands,  of  the  type  of  Krause's  glands  of  the  conjunc- 
tiva. Mucous  glands,  according  to  him,  have,  thus  far,  been 
found  with  certainty  only  at  the  orifice  of  the  nasal  lacrymal 
duct  in  the  nose,  and  it  is  still  a  moot  question,  whether  these 
mucous  glands  belong  in  reality  to  the  nasal  lacrymal  duct  or 
to  the  mucous  membrane  of  the  nose.  This  investigator  has, 
therefore,  seen  only  one  form  of  glandular  tissue  lying  in  the 
walls  of  the  lacrymal  sac,  namely  the  acinous  form,  which 
seems  to  be  the  most  frequent  one  of  the  two  forms  which  I 
have  found  and  described. 

It  is  a  strange  fact,  that  aside  from  Waldeyer's  article  in 
Graefe  &  Saemisch's  Cyclopaedia,  mentioned  above,  and  its 
translation  into  French  in  De  Wecker's  Traite  complet 
d'ophtalmologie,  and  of  the  parts  referring  to  the  eyelids  and 
lacrymal  apparatus  in  Fuchs'  text-book,  the  text-books  on 
ophthalmology  in  general  deal  but  very  insufficiently  with  the 
glandular  structures  which  are  the  subject  of  these  investiga- 
tions. Especially,  in  the  first  volume  of  the  large,  very 
recent,  and  generally  admirable  system  of  diseases  of  the  eye, 
published  by  Norris  &  Oliver,  Philadelphia,  1897,  in  the  able 
article  on  the  anatomy  of  the  orbit  and  the  appendages  of 
the  eye  by  T.  Dwight,  these  points,  it  seems  to  me,  are  passed 
over  too  lightly.  The  lacrymal  caruncle,  for  instance,  though 
not  a  very  important  organ,  might  have  received  a  little 
more  attention  than  is  expressed  in  the  following  words :  "  A 
raised  pinkish  little  body,  the  lacrymal  caruncle  (Vol.  I,  p. 
80)."  The  largest  amount  of  the  literature  on  the  subjects 
here  considered,  is  dispersed  in  journals  and  magazines 
which  are  not,  as  a  rule,  even  ophthalmological  ones,  and  it 
is,  therefore,  not  easily  obtained. 

With   regard   to   the   small   portion    of   hyaline   cartilage 


19 

tissue  which  in  one  instance  I  found  just  below  the  lacrymal 
caruncle,  I  have  detected  only  one  statement  in  literature  of 
a  somewhat  similar  occurrence.  In  the  text-book  of  A. 
Boehm  and  M.  von  Davidoff  *  the  following  statement  is 
made  (p.  349):  "  The  third  eyelid,  the  plica  semilunaris, 
when  well  developed,  contains  a  small  spicule  of  hyaline 
cartilage." 

In  illustrating  the  details  of  their  descriptions  of  the  eye- 
lids, most  text-books  give  a  longitudinal  (sagittal)  section 
through  the  thickness  of  the  upper  lid  near  the  temporal 
canthus.  From  the  descriptions  here  given,  it  is  clear  that 
one  such  drawing  (not  even  excluding  Waldeyer's  often 
copied  and  classical  one)  cannot  be  sufficient,  as  the  details 
of  the  tissues  of  the  eyelids  differ  so  very  materially  in  their 
different  portions  (Figs.  69  to  71). 

EXPLANATION  OF  ILLUSTRATIONS. 
PLATES  I-XXXVI. 

Plate  I.  —  1,  Vertical  (sagittal)  section  through  the  orbital  lacrymal 
gland  (A)  and  the  more  compact  portion  of  the  inferior  or  palpebral  lacry- 
mal gland  (B),  from  a  negro. — 2,  Vertical  (sagittal)  section  through  the 
temporal  outer  third  of  the  upper  eyelid  and  the  eyeballj  from  a  white  indi- 
vidual, showing  the  orbital  and  part  of  the  palpebral  lacrymal  gland.  —  3, 
Section  the  same  as  in  Fig.  2,  from  a  negro.  The  magnifying  power  under 
which  the  last  two  photographs  were  taken  being  the  same,  the  great  differ- 
ence in  size  of  the  two  orbital  lacrymal  glands  is  evident. 

Plate  II.  —  4,  From  a  negro.  Section  the  s:<me  as  in  Figs.  2  and  3, 
but  still  further  toward  the  temporal  canthus,  showing  a  large  number  of 
lobules  belonging  to  the  palpebral  lacrymal  gland. 

Plate  III.  —  5,  Part  of  the  palpebral  lacrymal  gland  of  Fig.  2  under  a 
higher  magnifying  power.  Above,  part  of  the  orbital  lacrymal  gland ;  to  the 
left,  the  orbicularis  muscle;  to  the  right,  the  conjunctiva,  sclerotic  and 
choroid.  The  palpebral  gland  is  seen  to  be  separated  from  the  orbital  one 
by  the  tendon  of  the  levator  palpebrae  superioris  and  the  nonstriated  muscle 
of  Mueller.  —  6,  Vertical  (sagittal)  section  through  both  eyelids  at  the 
temporal  canthus,  showing  lobules  of  the  palpebral  lacrymal  gland  in  the 
lower  eyelid  as  well  as  in  the  upper  one,  from  a  negro. 

Plate  IV.  —  7,  Vertical  (sagittal)  section  through  the  lower  eyelid 
near  the  temporal  canthus  (white),  showing  a  Meibomian  gland  (A),  below 
it  acino-tubular  glands  (B),  and  below  these,  three  lobules  of  the  lower 


*  Lehrbuch  der  Histologie  des  Menschen,  einschliesslich    der  mikros- 
kopischen  Technik.    Wiesbaden.  1898. 


20 

palpebral  lacrymal  gland  with  an  excretory  duct  between  them.  To  the  left 
the  orbicularis  muscle.  —  8,  Vertical  (sagittal)  section  through  the  upper 
eyelid  and  eyeball  (white),  just  through  the  middle  line.  The  small  round 
dark  body  in  the  subconjunctival  tissue  above  the  tarsus  (-*)  is  an  iso- 
lated small  lacrymal  gland. 

Plate  V.  —  9,  The  same  lacrymal  glands  as  in  Fig.  8,  under  a  high 
magnifying  power.  — 10,  Three  lobules  of  the  palpebral  lacrymal  gland  in 
the  upper  eyelid,  and  an  excretory  duct. 

Plate  VI.  — 11,  The  distal  end  and  external  orifice  of  one  of  the  ex- 
cretory ducts  of  the  orbital  lacrymal  gland  (vertical  section).  —  12,  Several 
lobules  of  the  palpebral  lacrymal  gland  of  the  upper  eyelid;  upwards 
an  excretory  duct  from  the  orbital  lacrymal  gland.  The  epithelium  of  the 
conjunctiva  has  fallen  off. 

Plate  VII.  —  13,  Vertical  section  through  two  lobules  of  the  palpe- 
bral gland,  one  with  its  excretory  duct,  upper  eyelid.  —  H,  A  large  lobule 
of  the  palpebral  lacrymal  gland  with  its  excretory  duct,  upper  eyelid. 

Plate  VIII.  — 15,  A  large  lobule  of  the  palpebral  lacrymal  gland  with  its 
excretory  duct.  To  the  right  of  it  a  transverse  section  of  an  excretory 
duct  from  the  orbital  lacrymal  gland.  The  conjunctival  epithelium  has 
fallen  off. — 16,  The  external  orifice  of  the  excretory  duct  of  a  small  iso- 
lated lacrymal  gland  in  the  conjunctiva.  Lymphatic  infiltration  around  and 
near  it.  To  the  left  the  bulbar  conjunctiva.  The  epithelium  has  fallen  off. 
Plate  IX.  —  17,  Small  acinous  gland  in  the  upper  eyelid  close  to  the 
nasal  canthus  ("•*).  Vertical  section  through  upper  eyelid  and  eyeball. 
The  lacrymal  caruncle  is  seen  below.  —  18,  The  same  gland  under  a  higher 
magnifying  power. 

Plate  X.  — 19,  20,  Acinous  glands  from  the  conjunctiva  near  the 
lacrymal  caruncle,  upper  eyelid. 

Plate  XI.  — 21,  Horizontal  section  through  the  lower  eyelid  a  little 
below  the  caruncle.  An  acinous  gland  imbedded  in  the  loose  connective 
tissue.  Upwards  to  the  left  side  the  conjunctival  sac.  —  22,  A  part  of  the 
same  gland  and  its  duct  under  a  higher  magnifying  power. 

Plate  XII.  —  23,  Horizontal  section  through  the  eyelids  showing  the 
tarsal  tissue,  including  some  Meibomian  glands,  some  acino- tubular  glands 
in  the  middle  line,  and  small  acinous  glands  in  the  conjunctiva  at  both  the 
temporal  and  nasal  edges  of  the  tarsus  (A,  B).  —  24,  The  same.  The  skin 
and  orbicular  muscle  torn  off. 

Plate  XIII.  —25,  Similar  section  to  Figs.  23  and  24.  —  The  dark  lines 
in  the  conjunctiva  represent  the  lymphatic  infiltration.  —  26,  Somewhat  ob- 
lique vertical  section  through  the  upper  eyelid,  showing  the  lower  part  of  a 
Meibomian  gland  and  its  excretory  duct.  To  the  right  of  it  appears  to  be  a 
second  layer  of  glandular  tissue;  this  is,  however,  only  apparent  and  due  to 
the  obliqueness  of  the  section.  To  the  right  of  the  excretory  duct  lies  the 
muscle  of  Riolan  and  the  dark  root  of  an  eyelash  (negro) . 

Plate  XIV. — 27,  Vertical  section  through  the  tarsal  tissue  and  Mei- 
bomian glands  parallel  to  the  surface,  from  the  lower  eyelid,  close  to  the 
conjunctival  surface.  —  29,  Section  parallel  to  the  surface  through  the  tem- 
poral third  of  the  upper  eyelid,  showing  Meibomian  glands  with  dilated 
central  ducts,  and  above  them  the  acino-tubular  gland  as  dark  patches. 

Plate  XV.  — 28,  Similar  section  to  that  shown  in  Fig.  27. 


21 

Plate  XVI.  —  30,  The  same  section  as  shown  in  Fig.  29,  from  the 
lower  eyelid.  Near  the  lidmargin  in  both  of  these  figures  a  number  of  di- 
lated modified  sweat-glands  appear  as  small  white  spots.  —  81,  Horizontal 
section  from  near  the  upper  edge  of  the  tarsus  of  the  upper  eyelid,  showing 
the  acino- tubular  glands  in  the  temporal  side;  also,  a  small  acinous  gland  in 
the  conjunctiva.  Below  is  seen  the  bulbar  conjunctiva. 

Plate  XVII.  —  32,  Horizontal  section  through  the  tarsus  of  the  upper 
eyelid  just  above  the  uasal  canthus.  There  are  a  number  of  transverse  sec- 
tions of  Meibomian  glands  and  a  large  compact  body  of  acino-tubular  glands 
in  the  nasal  part  of  the  tarsus  (A) .  —  33,  Horizontal  section  through  the 
central  part  of  the  upper  eyelid.  In  the  middle  line  acino-tubular  glands 
are  seen  lying  between  the  Meibomian  glands  at  A. 

Plate  XVIII. —  34,  Section  the  same  as  in  Fig.  33,  but  nearer  the  lid- 
margin.  In  the  middle  line,  at  A,  a  small  piece  of  an  acino-tubular  gland 
with  its  excretory  duct  is  seen ;  also,  its  external  orifice  in  the  palpebral 
conjunctiva.  — 35,  A  similar  section  under  a  higher  magnifying  power.  To 
the  right  and  left  side  of  the  acino-tubular  gland  a  Meibomian  gland  is 
seen. 

Plate  XIX.  —  36,  Vertical  section  through  the  lower  eyelid,  near  the  tem- 
poral canthus.  Downwards,  the  very  much  dilated  central  duct  of  a  Mei- 
bomian gland;  above  it  a  number  of  acino-tubular  glands,  undergoing 
atrophy.  The  conjunctiva  to  the  right  shows  changes  due  to  chronic 
blennorrhoea.  —  37,  Acino-tubular  gland  from  the  upper  eyelid  under  a  high 
magnifying  power.  A  great  many  acini  are  atrophied. 

Plate  XX 38,  Vertical  section  of  the  upper  eyelid;  high  magnifying 

power.  In  the  left  lower  corner  the  dilated  apex  of  a  Meibomian  gland; 
above  it  lobules  of  an  acino-tubular  gland  torn  apart  in  mounting;  also  an 
excretory  duct  with  its  external  orifice  in  the  palpebral  conjunctiva.  The  con- 
junctival  epithelium  has  fallen  off.  —  39,  A  concretion  in  the  excretory  duct  of 
an  acino-tubular  gland  close  to  its  external  orifice  in  the  palpebral  conjunc- 
tiva, the  epithelium  of  which  has  fallen  off.  This  concretion  was  semi-soft 
and  took  up  those  stains  with  preference  for  which  mucous  substances  have 
a  special  affinity. 

Plate  XXI.  —  40,  Two  horizontal  sections  through  the  lidmargin.  The 
upper  one,  from  the  upper  eyelid,  goes  through  the  shafts  of  the  eyelashes; 
the  lower  one,  from  the  lower  eyelid,  goes  through  the  bulbs  of  the  eye- 
lashes. Both  sections  show  numerous  transverse  sections  through  Meibo- 
mian and  modified  sweat-glands,  as  light  spots.  —  41,  Vertical  (sagittal) 
section  through  the  margin  of  the  upper  eyelid :  A,  Meibomian  gland  and 
its  duct;  B  and  E,  eyelashes  and  their  sebaceous  glands;  C,  modified  sweat- 
gland;  at  D,  the  collecting  chamber  and  excretory  duct  which  does  not 
enter  the  sebaceous  gland  of  an  eyelash,  but  has  a  separate  orifice  at  the 
lidmargin;  at  F,  a  part  of  another  modified  sweat-gland  is  seen. 

Plate  XXII.  —  42,  Vertical  (sagittal)  section  through  the  margin  of  the 
lower  eyelid  of  a  negro.  To  the  left,  the  conjunctiva,  tarsus  and  a  Meibo- 
mian gland  with  its  excretory  duct  below ;  to  the  right,  the  skin  of 
the  eyelid;  downwards,  an  eyelash,  and  just  above  it  a  modified  sweat-gland 
with  its  secretory  duct,  the  external  orifice  of  which  lies  in  the  duct  of  a 
sebaceous  gland;  above  this  the  root  of  an  eyelash  and  the  orbicularis 
muscle.  Between  the  lower  end  of  the  Meibonuan  gland  and  the  sebaceous 


22 

gland  lies  Riolan's  muscle.  — 43,  Horizontal  section  through  the  lidmargin 
at  the  level  of  the  roots  of  the  eyelashes,  showing  numerous  transverse 
sections  of  hair-bulbs  and  between  them  modified  sweat-glands.  Down- 
wards the  transverse  sections  of  three  Meibomian  glands  near  their  lower 
end.  The  fibres  seen  running  parallel  to  the  conjunctival  surface  above  the 
Meibomian  glands  and  those  between  the  modified  sweat-glands  and  the  hair- 
bulbs  are  the  fibres  of  Riolan's  muscle. 

Plate  XXIII.  —  44,  45,  Vertical  sections,  parallel  to  the  surface,  through 
the  lid  margins  of  the  upper  and  lower  eyelid,  showing  the  modified  sweat- 
gland  and  Cabnormally  dilated),  between,  the  roots  and  shafts  of  the  eye- 
lashes, under  a  high  magnifying  power. 

Plate  XXIV.  —  46,  Section  the  same  as  in  Figs.  44  and  45,  showing  at  A, 
B  and  C  modified  sweat-glands  under  a  high  power,  having  an  altogether 
tubular  appearance;  above  them  are  some  acini  of  a  Meibomian  gland.  —  47, 
Horizontal  section  through  the  lacrymal  caruncle  of  a  negro,  showing 
sebaceous  glands,  the  transverse  section  of  a  hair  (upwards)  and  an  acinous 
gland  at  A. 

Plate  XXV.  —  48,  Vertical  section  through  a  lacrymal  caruncle  having 
two  acinous  glands  (A  and  B) .  The  epithelium  has  fallen  off.  —  49,  Hori- 
zontal section  through  the  lacrymal  caruncle.  Acinous  glands  at  A. 

Plate  XXVI.  —  50,  Similar  section  to  that  shown  in  Fig.  49.  —  51,  Small 
body  of  hyaline  cartilage  lying  in  the  loose  tissue  (in  one  lid  only)  of  the 
lower  eyelid,  just  below  the  caruncle.  Horizontal  section.  The  conjunc- 
tival epithelium  has  fallen  off. 

Plate  XXVII.  —  52,  This  cartilage  under  a  high  magnifying  power.  — 
53,  Vertical  (sagittal)  section  through  both  eyelids  passing  through  the 
vertical  portion  of  the  lacrymal  canaliculus  of  the  upper  eyelid  and  its 
orifice  in  the  lacrymal  papilla.  The  oblique  section  through  the  horizontal 
portion  of  the  canaliculus  is  seen  in  the  lower  eyelid.  The  canaliculus  is. 
filled  with  desquamated  epithelium. 

Plate  XXVIII. —  54,  Horizontal  section  through  the  upper  eyelid  showing 
the  horizontal  portion  of  the  lacrymal  canaliculus.  Below  is  the  lacrymal 
caruncle.  —  55,  Section  through  the  axis  of  the  lacrymal  papilla  and  the 
vertical  portion  of  the  lacrymal  canaliculus,  showing  its  narrowest  part  just 
inside  of  the  lacrymal  punctum,  from  where  it  widens  out  gradually  to  where 
it  bends  to  form  the  horizontal  portion. 

Plate  XXIX.  —  56,  Section  like  the  one  in  Fig.  55.  To  the  left  the  hori- 
zontal diverticle  of  the  lacrymal  canaliculus  projects  into  the  tissue  of  the 
eyelid  (temporally) ,  to  the  right  (nasally)  the  beginning  of  the  horizontal 
portion.  This  section  does  not  pass  exactly  through  the  axis  of  the  vertical 
portion  of  the  canaliculus.  —  57,  Horizontal  section  showing  a  tortuous 
lacrymal  canaliculus. 

Plate  XXX.  —  58,  Section  through  both  eyelids  and  nasal  canthus  almost 
parallel  to  their  surface.  To  the  left  and  downwards,  nasal  part  of  the 
upper, to  the  right  and  upwards,  nasal  part  of  the  lower  eyelid ;  between  these 
the  lacrymal  caruncle.  At  the  right  the  horizontal  portions  of  the  two  can- 
aliculi  are  seen  to  join  at  a  sharp  angle.  —59,  The  entrance  of  the  lacrymal 
canaliculus  into  the  lacrymal  sac.  The  canaliculus  lies  to  the  right  and  is 
seen  to  be  lined  with  a  thick  pavement  epithelium ;  the  lacrymal  sac  to  the 
left  is  lined  with  cylindrical  epithelium, 


23 

Plate  XXXI.  —  60,  Horizontal  section  through  the  right  lower  eyelid  (A) 
and  the  tissue  at  the  side  of  the  nose.  The  lacrymal  sac  at  B. 

Plate  XXXII.  —  61,  the  walls  of  the  lacrymal  sac,  showing  the  cylindrical 
epithelium  and  lymphatic  infiltration,  under  a  high  magnifying  power.  —  62, 
Acinous  glands  in  the  wall  of  the  lacrymal  sac  at  A. 

Plate  XXXIII.  —  63,  Similar  section  to  Fig.  62,  —  64,  Acinous  gland  of  the 
lacrymal  sac.  The  sac  begins  to  the  right  downwards;  the  gland  seems  to 
lie  some  distance  from  it. 

Plate  XXXIV.  —  65,  Another  such  acinous  gland,  with  an  oblique  section 
through  its  excretory  duct.  —  66,  Several  acini  of  such  a  gland  from  the  wall 
of  a  lacrymal  sac,  under  a  high  magnifying  power. 

Plate  XXXV.  —  67,  68,  Glands  in  the  wall  of  a  lacrymal  sac  which  have  a 
more  tubular  structure. 

Plate  XXXVI.  —  69,  Schematic  section  through  both  eyelids  and  eyeball 
near  the  nasal  canthus.  —  70,  Schematic  section  through  the  middle  line  of 
both  eyelids  and  eyeball.  —  71,  Schematic  section  through  both  eyelids  and 
eyeball  near  the  temporal  canthus. 

Issued  July  12,  1900. 


PLATE  I. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  II. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  III. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  IV. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  V. 


J 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE   VI. 


11 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  VII. 


H 
GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  VIII. 


A 


15 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  IX. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  X. 


19 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XL 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XII. 


23 


•24 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XIII. 


(i LANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XIV. 


'27 


29 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XV 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XVI. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XVII. 


32 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XVIII. 


35 
GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XIX. 


86 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XX. 


89 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


•LATE  XXI. 


40 


1.  _. 


41 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXII. 


48 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XX I II. 


44 


4.-, 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXIV. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXV. 


GLANDS  APPERTAINING  TO  HUMAN   EYE. 


PLATE  XX  VI. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXVII. 


1 '. 

4v, 


52 


58 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXVIII. 


55 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXIX. 


57 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXX. 


r 


r>s 


59 
GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXXI. 


Jl 


60 


ULAXDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXXII. 


81 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  xxxill. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXXIV. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXXV 


(18 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


PLATE  XXXVI. 


GLANDS  APPERTAINING  TO  HUMAN  EYE. 


DATE   DUE  SLIP 

UNIVERSITY  OF  CALIFORNIA  MEDICAL  SCHOOL  LIBRARY 

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CCT  13 


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24521 


